切根和截顶对湿地松苗木质量的影响

研究了切根和截顶对湿地松苗木质量的影响，结果表明：（1）不同的切根处理对湿地松苗高和地径的生长有显著抑制作用，几种处理中，以9月份切根对苗高的抑制最小，以3次切根的处理对地径生长的抑制作用最小，但切根处理对湿地松苗木的高径比影响较小；（2）几种切根处理中，只有1次切根处理下地上部分的干重大于对照，2次切根处理根系干重最小，全苗干重以1次处理时最大，其次为对照；（3）不同的截顶处理下，湿地松苗高和地径生长都比对照低，单次截顶的苗高均比2次截顶的高，地径生长以9月中旬处理的较大；（4）几种截顶处理中，根干重和侧须根干重都比对照低，其中8月中旬截顶处理下苗木生长最慢，单次截顶处理的侧主根干重均大于对照，全苗干重都明显小于对照。

Effects of Root-pruning and Top-pruning on Seedling Quality of Pinus elliottii

The effects of root-pruning and top-pruning on seedling quality of Pinus elliottii were studied.The results are as follows:The root-pruning had a negative influence on seedling height and base diameter growth.The root-pruning damaged the root system and therefore had effect on the absorption of the water and effective fertilizers,and made some growing abilities on lands of the seedlings decline.Pruning time had an obvious impact on the seedling growth:the root pruning in August was more effective than that in September.Root-pruning for more than two times was more effective than the root pruning once a year.Top-pruning hindered the seedling growth in certain period.The seedling height and base diameter of the seedling with top pruning were shorter than those for the compared seedling,and there were significant effects on the early top-pruning treatment.The net weights of the main roots,branch roots,and the total net weight of the root system decreased and the ratio of the branch roots and the main roots increased a little,which indicated that the top-pruning had a negative impact on the growth of the root system.